Canada’s Calvalley Petroleum has resumed crude oil shipments from its Block 9 central processing facility in Yemen after attacks on its road tankers.

Production at the Hiswah and Ras Nowmah fields is now estimated to total between 5,100-5,300 barrels a day (b/d), having been restricted to 4,000 b/d following the attacks, according to a 21 March company statement.

Several of the contractor’s truck units, hauling approximately 3,800 barrels of crude oil were damaged by unknown assailants, Calvalley reported on 15 March.

Production is loaded onto trucks and sent to an offloading facility at Block 51, which is operated by Nexen, another Canadian oil exploration firm.

Calvalley has a 50 per cent stake Block 9 of the Masila Basin in central Yemen. India’s Reliance Industries (RIL) holds 25 per cent and the local Hood Oil owns the remaining 25 per cent.

Yemen’s oil sector has been hampered by repeated attacks on its oil infrastructure over the past year. Production in mid-2011 was reduced to less than 50 per cent, from 274,000 b/d due to the disruption of the Marib oil export pipeline.